From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DBADE1AC8AC; Thu, 26 Sep 2024 09:54:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727344453; cv=none; b=jZlCwSOH030S4BV3xdLVw7BXwzPvz5fA21xeWcN5Z9jcfT5VLfN2SsRyW7zPw1Lk5HyhAr2/JSElv94u/wW/Udpw45wgGvgazUOIjs7+c+HoRzn+yXFo2g2/Nx8ZdXHpSr6umSlPxM1ii0vMsKXG2Gw7gT1RAJioGOTGgE4fwCE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727344453; c=relaxed/simple; bh=UrgLpRfgJrNUnHEwNNEt7LcLrQn38ti4wGH3zdUBp7E=; h=Mime-Version:Content-Type:Date:Message-Id:Subject:From:To:Cc: References:In-Reply-To; b=OzNb5SrJ7xhjnZwLLCwv1AJyCIkoltQsJN/NT/J0wc/YWiTaSlcUM58wFIpKOmeNKhx/3qqo3aH9sHPoifwb28ktek8GRRCNI727r0+Lcc2Yrv8YHaGZLfhVblImck33RpCBPmMPSeC2a4bG1K1U5r5oF2cjTeoc292T+GKGG7U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=er7Gvc2Z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="er7Gvc2Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 005D7C4CEC9; Thu, 26 Sep 2024 09:54:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727344452; bh=UrgLpRfgJrNUnHEwNNEt7LcLrQn38ti4wGH3zdUBp7E=; h=Date:Subject:From:To:Cc:References:In-Reply-To:From; b=er7Gvc2ZmiWuI70tPYhcBLFqTKmQQhn1k5IwrIOTQrRGNr5hAuNUHUqR0ywrVMNd6 YHokSOfBaKdVPodHvFv2by50o1aJFSCM3sAFBItP4JGhxnVNyTFahwl4nunlFfh2FF JKpzlbROWvpHo5tdMI5lacBsfMHugEPc2uVEyYvFLAOOc3k3GcCyB9ZX/K3+I6EJNH oQ191FHX7J7DZ948+W9e9BXknyznwEvUY2kUtD236UOJVqUHyXBXYJVa8jtdEkHNEs UX9tKueJn4cGnyJAFPyqgFpb9cqwQL81oILOY0A+yYgYrEIGnk9b3AIVIr6pQn1SXk EiiWdIPdWbdIg== Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Thu, 26 Sep 2024 12:54:08 +0300 Message-Id: Subject: Re: [PATCH] security/keys: fix slab-out-of-bounds in key_task_permission From: "Jarkko Sakkinen" To: "Jarkko Sakkinen" , "Chen Ridong" , "Chen Ridong" , , , , Cc: , , , , X-Mailer: aerc 0.18.2 References: <20240913070928.1670785-1-chenridong@huawei.com> <4079d020-edcc-4e27-9815-580f83a6c0ca@huaweicloud.com> <1cfa878e-8c7b-4570-8606-21daf5e13ce7@huaweicloud.com> In-Reply-To: On Thu Sep 26, 2024 at 11:55 AM EEST, Jarkko Sakkinen wrote: > On Thu Sep 26, 2024 at 11:53 AM EEST, Jarkko Sakkinen wrote: > > On Thu Sep 26, 2024 at 6:48 AM EEST, Chen Ridong wrote: > > > > > > On 2024/9/19 4:57, Jarkko Sakkinen wrote: > > > > On Wed Sep 18, 2024 at 10:30 AM EEST, Chen Ridong wrote: > > > >> > > > >> > > > >> On 2024/9/15 21:59, Jarkko Sakkinen wrote: > > > >>> On Sun Sep 15, 2024 at 3:55 AM EEST, Chen Ridong wrote: > > > >>>> > > > >>>> > > > >>>> On 2024/9/14 19:33, Jarkko Sakkinen wrote: > > > >>>>> On Fri Sep 13, 2024 at 10:09 AM EEST, Chen Ridong wrote: > > > >>>>>> We meet the same issue with the LINK, which reads memory out o= f bounds: > > > >>>>> > > > >>>>> Nit: don't use "we" anywhere". > > > >>>>> > > > >>>>> Tbh, I really don't understand the sentence above. I don't what > > > >>>>> "the same issue with the LINK" really is. > > > >>>>> > > > >>>> > > > >>>> Hello, Jarkko. > > > >>>> I apologize for any confusion caused. > > > >>>> > > > >>>> I've encountered a bug reported by syzkaller. I also found the s= ame bug > > > >>>> reported at this LINK: > > > >>>> https://syzkaller.appspot.com/bug?id=3D68a5e206c2a8e08d317eb83f0= 5610c0484ad10b9. > > > >>>> > > > >>>>>> BUG: KASAN: slab-out-of-bounds in __kuid_val include/linux/uid= gid.h:36 > > > >>>>>> BUG: KASAN: slab-out-of-bounds in uid_eq include/linux/uidgid.= h:63 [inline] > > > >>>>>> BUG: KASAN: slab-out-of-bounds in key_task_permission+0x394/0x= 410 > > > >>>>>> security/keys/permission.c:54 > > > >>>>>> Read of size 4 at addr ffff88813c3ab618 by task stress-ng/4362 > > > >>>>>> > > > >>>>>> CPU: 2 PID: 4362 Comm: stress-ng Not tainted 5.10.0-14930-gafb= ffd6c3ede #15 > > > >>>>>> Call Trace: > > > >>>>>> __dump_stack lib/dump_stack.c:82 [inline] > > > >>>>>> dump_stack+0x107/0x167 lib/dump_stack.c:123 > > > >>>>>> print_address_description.constprop.0+0x19/0x170 mm/kasan/= report.c:400 > > > >>>>>> __kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560 > > > >>>>>> kasan_report+0x3a/0x50 mm/kasan/report.c:585 > > > >>>>>> __kuid_val include/linux/uidgid.h:36 [inline] > > > >>>>>> uid_eq include/linux/uidgid.h:63 [inline] > > > >>>>>> key_task_permission+0x394/0x410 security/keys/permission.c= :54 > > > >>>>>> search_nested_keyrings+0x90e/0xe90 security/keys/keyring.c= :793 > > > >>>>>> keyring_search_rcu+0x1b6/0x310 security/keys/keyring.c:922 > > > >>>>>> search_cred_keyrings_rcu+0x111/0x2e0 security/keys/process= _keys.c:459 > > > >>>>>> search_process_keyrings_rcu+0x1d/0x310 security/keys/proce= ss_keys.c:544 > > > >>>>>> lookup_user_key+0x782/0x12e0 security/keys/process_keys.c:= 762 > > > >>>>>> keyctl_invalidate_key+0x20/0x190 security/keys/keyctl.c:43= 4 > > > >>>>>> __do_sys_keyctl security/keys/keyctl.c:1978 [inline] > > > >>>>>> __se_sys_keyctl+0x1de/0x5b0 security/keys/keyctl.c:1880 > > > >>>>>> do_syscall_64+0x30/0x40 arch/x86/entry/common.c:46 > > > >>>>>> entry_SYSCALL_64_after_hwframe+0x67/0xd1 > > > >>>>>> > > > >>>>>> However, we can't reproduce this issue. > > > >>>>> > > > >>>>> "The issue cannot be easily reproduced but by analyzing the cod= e > > > >>>>> it can be broken into following steps:" > > > >>>> > > > >>>> Thank you for your correction. > > > >>>> Does this patch address the issue correctly? Is this patch accep= table? > > > >>> > > > >>> I only comment new patch versions so not giving any promises but = I can > > > >>> say that it is I think definitely in the correct direction :-) > > > >>> > > > >>> BR, Jarkko > > > >> > > > >> Hello, Jarkko. I have reproduced this issue. It can be reproduced = by > > > >> following these steps: > > > >> > > > >> 1. Add the helper patch. > > > >> > > > >> @@ -205,6 +205,9 @@ static void hash_key_type_and_desc(struct > > > >> keyring_index_key *index_key) > > > >> else if (index_key->type =3D=3D &key_type_keyring && (ha= sh & > > > >> fan_mask) !=3D 0) > > > >> hash =3D (hash + (hash << level_shift)) & ~fan_m= ask; > > > >> index_key->hash =3D hash; > > > >> + if ((index_key->hash & 0xff) =3D=3D 0xe6) { > > > >> + pr_err("hash_key_type_and_desc: type %s %s > > > >> 0x%x\n", index_key->type->name, index_key->description, index_key= ->hash); > > > >> + } > > > >> } > > > >> > > > >> 2. Pick up the inputs whose hash is xxe6 using the following cmd. = If a > > > >> key's hash is xxe6, it will be printed. > > > >> > > > >> for ((i=3D0; i<=3D10000; i++)); do ./test_key user user$i "Some pa= yload"; done > > > >> > > > >> You have complile test_key whith following code. > > > >> > > > >> #include > > > >> #include > > > >> #include > > > >> #include > > > >> #include > > > >> #include > > > >> > > > >> int > > > >> main(int argc, char *argv[]) > > > >> { > > > >> key_serial_t key; > > > >> > > > >> if (argc !=3D 4) { > > > >> fprintf(stderr, "Usage: %s type description payload\n", > > > >> argv[0]); > > > >> exit(EXIT_FAILURE); > > > >> } > > > >> > > > >> key =3D add_key(argv[1], argv[2], argv[3], strlen(argv[3]), > > > >> KEY_SPEC_SESSION_KEYRING); > > > >> if (key =3D=3D -1) { > > > >> perror("add_key"); > > > >> exit(EXIT_FAILURE); > > > >> } > > > >> > > > >> printf("Key ID is %jx\n", (uintmax_t) key); > > > >> > > > >> exit(EXIT_SUCCESS); > > > >> } > > > >> > > > >> > > > >> 3. Have more than 32 inputs now. their hashes are xxe6. > > > >> eg. > > > >> hash_key_type_and_desc: type user user438 0xe3033fe6 > > > >> hash_key_type_and_desc: type user user526 0xeb7eade6 > > > >> ... > > > >> hash_key_type_and_desc: type user user9955 0x44bc99e6 > > > >> > > > >> 4. Reboot and add the keys obtained from step 3. > > > >> When adding keys to the ROOT that their hashes are all xxe6, and u= p to > > > >> 16, the ROOT has keys with hashes that are not xxe6 (e.g., slot 0)= , so > > > >> the keys are dissimilar. The ROOT will then split NODE A without u= sing a > > > >> shortcut. When NODE A is filled with keys that have hashes of xxe6= , the > > > >> keys are similar. NODE A will split with a shortcut. > > > >> > > > >> As my analysis, if a slot of the root is a shortcut(slot 6), it ma= y be > > > >> mistakenly be transferred to a key*, leading to an read out-of-bou= nds read. > > > >> > > > >> NODE A > > > >> +------>+---+ > > > >> ROOT | | 0 | xxe6 > > > >> +---+ | +---+ > > > >> xxxx | 0 | shortcut : : xxe6 > > > >> +---+ | +---+ > > > >> xxe6 : : | | | xxe6 > > > >> +---+ | +---+ > > > >> | 6 |---+ : : xxe6 > > > >> +---+ +---+ > > > >> xxe6 : : | f | xxe6 > > > >> +---+ +---+ > > > >> xxe6 | f | > > > >> +---+ > > > >> > > > >> 5. cat /proc/keys. and the issue is reproduced. > > > >=20 > > > > Hi, I'll try to run through your procedure next week and give my co= mments. > > > > Thanks for doing this. > > > >=20 > > > > BR, Jarkko > > > > > > Hi, Jarkko, have you run these procedure? > > > I have tested this patch with LTP and a pressure test(stress-ng --key= ),=20 > > > and this patch have fixed this issue. Additionally, no new bugs have= =20 > > > been found so far. > > > > > > I am looking forward to your reply. > > > > > > Best regards, > > > Ridong > > > > Nope because we are apparently stuck with release critical bug: > > > > https://lore.kernel.org/linux-integrity/D4EPMF7G3E05.1VHS9CVG3DZDE@kern= el.org/T/#t > > > > Might take several weeks before I look into this. > > I was expecting to send a PR early this week since the patch set > addresses the issue so thus wrong estimation. I asked David if he could look into this. BR, Jarkko